This invention relates to a method for making solar photocell panels useful in forming photoelectric batteries. Such panels comprise a plurality of photocells connected together electrically and having electrical output terminals or connectors. The photocells and their associated electrical connectors are embedded in at least one layer of plastic between two rigid sheets of which at least the sheet on the side of the receiving face of the photocells is transparent.
Solar photocells have as their main application the supplying of electrical energy to devices such as light beacons, land or maritime radio beacons, television retransmitters in mountainous areas, and the like.
In general, electrically interconnected solar photocells are arranged in batteries in the form of panels which are easy to mount and use. It is very important that a panel retain its structural, photovoltaic and electrical qualities over long periods of time. These objectives require that the surface elements of the photocell, such as silicon semiconductors, remain stable, which in turn requires that the photocells be protected from the atmosphere. Therefore, the panel must remain impervious to air and moisture, otherwise the output of the photocells will drop, because in practice, their useful lifetime is a function of the effectiveness with which they have been encapsulated.
On the other hand, in order to achieve a practical degree of electric power output, the panels must have sufficiently large dimensions. However, the cost of such panels is high since it depends on the cost of the semiconductors used, the cost of the mechanical support systems, and the amount of labor needed to make the panels, considering the care that must go into them.
Some types of solar panels have already appeared on the market. Unfortunately, it is very difficult to provide such panels that are free of bubbles or other defects using only two thermoplastic sheets of polyvinylbutyral, which is the most widely used resin for making laminated glass. For this reason, some panels have been made by placing a battery of interconnected photocells between two sheets of glass, and filling the spaces between the sheets and the photocells with a transparent resin in the form of a syrup that later solidifies, e.g., by polymerization. But panels prepared by this technique can have defects in homogeneity or bubbles that are introduced at the time the resin is injected, and such panels are considered unusable. Furthermore, this fabrication technique requires considerable care and time which of course increases the cost per installed solar watt.